In this paper, we propose an Identity (ID)-based Secure Routing Scheme for secure routing in wireless ad-hoc networks. It make use of Identity based Signature scheme and hash chains to secure the AODV (Ad-hoc on demand distance vector routing) messages. We have used ID based Signature scheme for the immutable fields, that is the fields that remain same throughout the journey of the routing packet and Hash Chains for the mutable fields (fields which changes from node to node) e.g. Hop Count. This system has the following advantages as compared to the previous solutions, most of which uses RSA based Public Key Cryptographic solutions. Firstly, it makes use of Identity based signature scheme which is certificateless thus saving overhead costs of communication and storage. Secondly, in ID based schemes we can use our identity, like our IP address or email ID as our public key, which leads to smaller key size as compared to other cryptographic techniques. Also this system does not require establishment of any third party like PKI (Public-key Infrastructure) at the initial stages of network establishment.

Introduction

A Mobile Ad hoc Network, or MANET, consists of a group of cooperating wireless mobile hosts (nodes) that dynamically constructs a short lived and self-configuring network without the support of a centralized network infrastructure. The mobile nodes can be cell-phones, PDAs and laptops and typically support wireless connectivity like 802.11, Bluetooth, etc. MANETs are fundamentally different from their wired-side counterparts. They provide no fixed infrastructure, base stations or switching centers. Moreover, the nodes of a MANET are computationally constrained and have limited power.
Routing is an important function in any network, be it wired or wireless. The protocols designed for routing in these two types of networks, however, have completely different characteristics. Routing protocols for wired networks typically do not need to handle mobility of nodes within the system. These protocols also do not have to be designed so as to minimize the communication overhead, since wired networks typically have high bandwidths. Very importantly, the routing protocols in wire line networks can be assumed to execute on trusted entities, namely the routers.
These characteristics change completely when considering ad hoc wireless networks. Mobility is a basic feature in such networks. Resource constraints like limited bandwidth and computing power of the devices also aggravates the problem of designing routing protocols for such networks which do not require high bandwidths. Ad hoc networks also do not have trusted entities such as routers, since every node in the network is expected to participate in the routing function. Therefore, routing protocols need to be specifically designed for wireless ad hoc networks.
Ad-hoc routing protocols, including AODV (Ad-Hoc Distance Vector Routing) , DSR (Dynamic Source Routing), OLSR (Optimized Link State Routing), etc are designed for performance, not security, and thus all of them are subjected to some kind of attacks. These attacks include, packet dropping, modification of packets (modifying sequence numbers, hop count, etc), impersonation, replaying of old routing information etc. These attacks can partition a network or may introduce excessive load into the network by causing retransmission and inefficient routing.
The Ad hoc On Demand Distance Vector (AODV)routing algorithm is a reactive routing protocol designed for ad hoc mobile networks. To transmit data over an adhoc network, the AODV protocol enables dynamic, selfstarting, multi-hop routing between mobile devices. It allows these mobile computers, or nodes, to pass messages through their neighbors to nodes with which they cannot directly communicate.

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